1. Field of the Invention
The object of the present invention is an automatic or semiautomatic firearm comprising a frame, a removable cartridge magazine in the frame, a cartridge elevator piston which is movable in the magazine, a spring in the magazine to raise the elevator piston by continuous pressure, a temporary retainer of the magazine in the frame activated by engagement in a notch provided in the wall of the magazine, a manual control to deactivate the retainer of the magazine and free the magazine when desired, a barrel close to the frame, a firing chamber forming a continuation of the barrel and intended to receive a cartridge from the magazine, a breech block movable back and forth on the frame and comprising means in order, after each firing of a cartridge, to extract the case of the cartridge fired from the chamber during its recoil and then during its return displace another cartridge from the magazine up to the firing chamber, and this up to the last cartridge of the magazine, at the end of the elevation stroke of the cartridge elevator piston.
2. Description of the Prior Art
In the known firearms of this type, such as, for instance, semiautomatic pistols, assault rifles and automatic pistols shooting in bursts, means are provided to facilitate and make easier the manipulations required of the user for the evacuation and replacement of a cartridge magazine, in order to check the number of cartridges remaining in his magazine, as well as to warn him of the exhaustion of them after the firing of the last cartridge.
These means comprise the retainer of the cartridge magazine and its deactivation control, which have already been mentioned, and, on many of these known firearms, a breech block lock, namely a mechanism adapted to keep the breech block open in recoil position after the firing of the last cartridge of the magazine.
The retainer of the cartridge magazine consists of a lever having a stop, which, under the continuous pressure of a spring, engages in a retention notch in the wall of the magazine upon arrival of the magazine in the intended place in the frame.
The deactivation control for the retainer of the magazine generally consists of a simple extension of the lever of said retainer out of the frame, said extension having at its end a pressing surface for the thumb or index finger of the user, particularly when said control is arranged in the immediate vicinity of the trigger of the firearm, at the top of the stock, for ergometric reasons. By pressing said surface against the pressure of the spring of the retainer, the stop of the latter is disengaged from the notch of the magazine, and the latter is freed and can be removed from the frame. The user can thus, at any time, remove the magazine from his firearm, not only to check the number of cartridges remaining or to replace it by another magazine, but also for reasons of safety, such as, for instance, in a stop-fire situation or in the event of the jamming of the firearms.
The breech block lock is a lever with return spring having a stop intended to engage in a retention notch in the movable breech block in order to maintain the breech block open in the recoil position. The engaging of this stop in the retention notch of the breech block is produced on the one hand, first of all, by application of the thrust of the cartridge elevator piston against the breech block lock after the chambering of the last cartridge of the magazine in the firing chamber and, on the other hand, in a second step, by penetration of said stop, under the effect of this thrust, into the retention notch of the movable breech block, slightly before the end of the recoil movement of the breech block resulting from the firing of the last cartridge.
After the firing of the last cartridge, the fact that the breech block remains open in recoil position avoids the need of the user of count the shots in order to know when the cartridge magazine has been exhausted, permits, on the firing range, visual verification from a distance that the firearm is actually empty and out of operation, and also avoids having the user find himself with the breech block closed and the firearm ready to fire on an empty firing chamber, which situation is disturbing for precision firing and definitely dangerous in combat. Furthermore, the fact that the breech block remains open may contribute to the cooling of the barrel.
After introduction of a new cartridge magazine, the user pulls the breech block back slightly more to the end of its recoil stroke in order to free the stop of the breech block lock from the retention notch in the breech, it moving away under the effect of the return spring and allows the breech block to start forward again in order to introduce the first cartridge from its magazine into the firing chamber, the firearm being thus again ready to fire.
In combat situation, it is obvious that the manipulations required by the changing of the cartridge magazine constitute a handicap for the user. The trend has therefore always been to seek means which make it possible to minimize this handicap.
Thus, in certain pistols, means are provided so that the putting in place of a new magazine triggers the return of the breech block, which has remained open after the firing of the last cartridge of the previous magazine and thus causes the chambering of the first cartridge of this new magazine.
The user is thus freed from the necessity of manipulating the breech block in order to chamber this first cartridge, and he no longer has to concern himself with deactivating the retainer of the empty magazine before replacing it by a new magazine.
However, this manipulation, which is necessary for the release of an empty cartridge, which by its nature uses the thumb or index finger of the hand of the user, results in a change in the manner in which the pistol is held in one's hand, which again is a handicap in a precision firing situation.
However, the fact that the breech block remains open in recoil position after the firing of the last cartridge of the magazine has only advantages.
In fact, while this indication of the arrival at the end of the cartridge magazine is useful on the firing range as a matter of safety and in order to avoid the user finding himself ready to fire on an empty chamber, it is less so in combat situations, and may even become disturbing when facing the adversary.